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The material in this paper presents many facets of new technology which are becoming available, with a discussion of the subsequent effects on people in the Earthmoving Industry. Particular emphasis is placed on technological change as it relates to individual opportunity and professional growth for engineers.

This paper concerns the utilization of a CAD system in the development of models for finite element analysis. The capabilities of such systems provide inherent advantages in the consulting engineering business where products from a wide variety of manufacturers are analyzed. One of the primary advantages is the reduction in time required to develop and document a finite element model. That reduction can be realized only after system familiarity is achieved -- model development for nontrivial structures is not automatic. Examples of several models developed on a CAD system are included in the discussion.

PTFE has arisen as a practical and cost effective lip seal component. This has only come about through a thorough understanding of the relationship between the design parameters of the PTFE seal and the functional aspects of PTFE processing and manufacturing.

This paper presents the results of an experimental program in which the head induced damage from real world pedestrian accidents was reproduced with an impactor. An accident investigation study aimed at obtaining the necessary information for reconstructing pedestrian accidents is discussed. Results of preliminary impact tests in which the mass and velocity of the impactor were varied are presented. Impactor output from reconstructions of the head-induced damage from 24 pedestrian accidents is related to the head injury sustained by the pedestrian in the accident. The paper concludes that it is feasible to use a head form impactor for the development of pedestrian head injury tolerance data.

The paper describes the straight forward procedure used for investigating and analyzing driveline torsional characteristics during development of the Steiger Panther 1000 series four wheel drive tractors. These procedures are applicable to vehicle drives designed with transmissions remote mounted from reciprocating engines and driven by a jackshaft. The final design incorporating a torsional dampener was substantiated by dynamic measurements on the actual system.

Fatigue in crane with particular reference to offshore cranes is briefly discussed, and field measurement records illustrating types of vibration experienced in crane structures are shown. Design rules against fatigue in a couple of recognized Crane standards are discussed. It is pointed out that these standards might be inadequate in the evaluation of fatigue in cranes. A modified procedure for evaluation of fatigue in offshore crane elements is pointed out. The method description is provided with data which should make practical evaluations possible. The material presented is not authorized and is only to be regarded as a contribution to the current research in this field.

A new configuration was developed for track-type tractors in the 500 kW–550 kW range to meet the market need for productive capabilities greater than those of any existing tractors. This paper identifies the design goals that were established for a tractor of this size; and it explains the major design features, such as modular construction and suspension for track rollers and idlers incorporated in the resultant 522 kW tractor. A review is presented of the test program that was required to assure that the configuration met the design goals.

A new integrated circuit transducer has been developed for engine oil pressure control in off-road and heavy duty vehicles. The design and development was directed at optimizing cost vs. performance trade-offs. Both, system and component level considerations have been incorporated to achieve the objective. Total error of less than 2% of full scale has been accomplished with possible further improvement using system options. Of particular interest is the structural design that meets environmental reliability and which can be extended for pressure control applications in pneumatic and hydraulic systems in off-road and heavy duty vehicles.

The manufacturers goal of maximizing product uptime and maintaining acceptable levels of repair costs is significantly influenced by diagnostics. Diagnostic aids such as test equipment, technical manuals, diagnostic procedures, combined with dealership service department operations, technical training and design of the manufacturers product line directly affect a service technician’s ability and capability to properly support a product. In an “ideal” diagnostic situation, results of reduced diagnostic error and repair costs, with improved product uptime and marketability are more readily achieved. The combined influence of all the factors affecting diagnostics are best considered in total, versus consideration of each factor separately.

In this paper, a mathematical model is used to determine the fuel-consuming characteristics of a typical crawler tractor with bulldozer under various opera ting regimes. The results are used to suggest various methods to reduce tractor fuel consumption.

Recently, application of electronics to construction machinery has proceeded rapidly, and various measuring techniques have been required for a large number of electronic control or monitoring systems. Measurement of true velocity notwithstanding the existence of shoe or wheel slips is one of them. Microwave Doppler radar is an ideal measuring method for the purpose and has been used in automotive applications for many years. However, these vehicular radars don’t provide satisfactory results in typical operating conditions of construction machinery. And there remains a lot of problems to be solved. For example, the relative error at low velocity of 1km/h or so must be reduced. In this paper, solutions of these problems based on data of the field computer simulations and mathematical analyses are described. This study led to the conclusion that the radar’s performance can be highly improved.

The ease of serviceability affects the total owning and operating cost of earthmoving and construction machinery. Equipment is purchased to do a job and do it effectively. Serviceability impacts on product effectiveness. In addition to ease of repair (repairability) and ease of maintenance (maintainability), serviceability includes ease of diagnosis. During machine development phases, serviceability must be developed along with other machine requirements. To produce desirable results, a planned, disciplined process with dealer and user input added to manufacturer’s input is required.

Many materials have emerged from the aerospace and defense industries that may have a significant impact on commercial vehicles in the future. Some of these new materials were investigated for their application on Class 8 trucks. The most promising materials were applied to prototype parts and installed on a test truck as part of a lightweight development program. Most of these materials have unique characteristics that require a more complex and rigorous design process than the equivalent design with a conventional material. The major obstacles to be overcome are the high cost of the raw material and the development of automated fabrication methods.

This paper describes the methods employed to attain very low vehicle tare weight in the development of a new line of high entry tilt cab highway tractors. Design criteria mandated no sacrifice in durability or reliability, and substantial improvements in driver space, ride, noise level and aerodynamic drag as compared to the old model. The methods used to define and organize the Engineering program are covered as well as the design and test methods employed. Specific examples are provided to illustrate the design, use of computer aided engineering such as finite element analysis and life prediction, as well as the use of accelerated testing procedures. Finally, the production vehicle is compared to the targets and to competition at introduction time where it placed lightest weight in its class.

This paper describes a machine that tests crawler tractor power trains through application of the four square principle. Two units coupled to form a “closed torque loop” require only power input sufficient to overcome frictional losses. A computer governs test operation - from monitoring system parameters to control of a gearbox for dynamic torque loop loading. The loads at selected points in the closed loop were found to be dependent upon the directions of machine rotation and torque. It was concluded that frictional losses in the closed loop caused significant differences in load levels at the driving and driven test units.

A closed-loop control system has been designed which will adjust dozer blade penetration to maximize work rate under typical dozing conditions. This paper explains the operation and requirements of such a system referred to as the Automatic Draft Power Controller (ADPC). This system is currently being developed for the Naval Construction Engineering Laboratory for use on large scale earthmoving projects. The control system described in this paper may also be applied to other types of earthmoving equipment besides bulldozers.

A new class 8 heavy truck interior system has been developed. Included are an injection molded structural foam dash, a compact heater-air conditioner unit, a new cab electrical system, and a new trim package. The system has been implemented into both cab-over-engine and conventional model vehicles.

The heavy duty truck industry in recent years has faced an ever greater demand for driver comfort and convenience features. This demand was met in the design of a new cab-over-engine truck cab by providing much more room within existing length and width limitations, greater adjustment to suit more drivers, “places to put things,” optimum control positions, and numerous component design features for more “livability.”

Certain multiply-articulated truck combinations are known to exhibit lightly damped trailer yaw motions in response to rapid inputs of steering. This paper clarifies the yaw response phenomenon and illustrates this characteristic for ten vehicle combinations which are currently in use in the U.S. The phenomenon of interest is described in terms of the “amplification” in lateral acceleration level experienced at the rear-most trailer of the combination with respect to the lateral acceleration level achieved at the truck or tractor. Results from two types of computerized simulation are presented; one representing a linear treatment of the vehicle and producing frequency response characteristics, and the other representing a rather complete nonlinear treatment of the vehicle and producing time history responses in an emergency obstacle-avoidance maneuver.

Transit authorities have increasingly found that the provision of economic services to their communities require more efficient operations. Higher capacity buses have been evaluated, and as a result of trials, have entered more widespread fleet service. Articulated buses have been employed and the improvement in public transport efficiency can be assessed from a consideration of the advantages, and constraints. The relative efficiency of articulated buses and competitive high capacity buses can be assessed in a similar manner. The final choice is largely dependent on the size of the initial investment in infrastructure adaptation and the resulting whole life operating costs.